Process for embedding or encircling polycrystalline materials in single crystal material

ABSTRACT

CRYSTALLINE GROWTH AT NUCLEATION SITES ON THE POLYCRYSTALLINE BODY DOES NOT OCCUR. IN AN EXEMPLARY EMBODIMENT, EPITAXIALLY GROWTH MONOCRYSTALLINE FERRITE EMBEDS POLYCRYSTALLINE METALLIC CONDUCTORS TO FORM A STRUCTURE USEFUL AS A MAGNETIC MEMORY.   A PROCESS FOR ENCIRCLING A POLYCRYSTALLINE BODY IN SINGLE CRYSTAL MATERIAL. A SINGLE CRYSTAL SEED IS PLACED IN A REACTOR ADJACENT THE POLYCRYSTALLINE BODY. CHEMICAL VAPOR DEPOSITION IS USED TO DEPOSIT EPITAXIALLY A SINGLE CRYSTAL MATERIAL ON THE SEED, GROWTH BEING CONTINUED UNTIL THE DEPOSIT BUILDS ONTO AND AT LEAST PARTIALLY SURROUNDS THE BODY. THE RATE OF DEPOSITION IS CONTROLLED SO THAT POLY-

April 13, 1971 R PULLIAM ETAL 7 3,574,679-

PROCESS FOR EMBEDDING 0R ENCIRCLING POLYCRYSTALLINE MATERIALS IN SINGLECRYSTAL MATERIAL Filed Jan. 25, 1965 2 Sheets-Sheet l l I w I 4 k u I I5 I II. I III I il I III I I! |l| I" l I IN'VENTORS I GEORGER. PULLIAMJOHN L- ARCHER BY 2 5C fimf w ATTORNEY Aprnl 13, 1971 R PULUAM ETAL3,574,579

PROCESS FOR EMBEDDING OR EN IRGLING POLYCRYSTALLINE MATERIALS IN SINGLECRYSTAL MATERIAL 7 Filed Jan. 25, 1965 2 Sheets-Sheet 2 FIG.4 l4

FIG. 3

- INVENTORS GEORGE R PULLI AM JOHN L. ARCHER ATTORNEY United StatesPatent 3,574,679 PROCESS FOR EMBEDDING OR ENCIRCLING POLYCRYSTALLINEMATERIALS IN SINGLE CRYSTAL MATERIAL George R. Pulliam and John L.Archer, Anaheim, Calif.,

assignors to North American Rockwell Corporation Filed Jan. 25, 1965,Ser. No. 427,804 Int. Cl. C23c 11/08 US. Cl. 117-212 Claims ABSTRACT OFTHE DISCLOSURE A process for encircling a polycrystalline body in singlecrystal material. A single crystal seed is placed in a reactor adjacentthe polycrystalline body. Chemical vapor deposition is used to depositepitaxially a single crystal material on the seed, growth beingcontinued until the deposit builds onto and at least partially surroundsthe body. The rate of deposition is controlled so that polycrystallinegrowth at nucleation sites on the polycrystalline body does not occur.In an exemplary embodiment, epitaxially grown monocrystalline ferriteembeds polycrystalline metallic conductors to form a structure useful asa magnetic memory.

This invention relates to a deposition process for embedding orencircling polycrystalline materials in single crystal materials.

Previous attempts to either embed or encircle a polycrystalline materialin a single crystalline material have resulted in a polycrystallinedeposition on the surface of the encapsulated polycrystalline material.In effect, the polycrystalline material was encapsulated in apolycrystalline deposition. Thus, the advantages of a single crystalembedment or encirclement were not realized.

For example, as the name implies, a single crystal material has onecontinuous crystalline structure and has uniform characteristicsthroughout its structure. Also, characteristics from one production runto another are uniform. The opposite result is true of polycrystallineproduction runs. It is difiicult to produce substantially identicalcharacteristics in polycrystalline materials. On the other hand, theproperties of single crystals are more predictable and, thus, theircontrollability is enhanced.

Single crystal magnetic materials are anisotropic and susceptible toeasy magnetization in a given crystallographic direction. Single crystalmaterials may, therefore, be used as magnetic memory devices.

In a polycrystalline material the easy direction of magnetization forall of crystals are not uniformly oriented and, therefore, point inrandom directions. In single crystal materials the easy direction ofmagnetization points in precise and known directions and is morepredictably rotated in response to an electrically produced magneticforce.

Since the single crystal material is more uniform throughout, in itsmagnetic characteristics, than polycrys talline material, less power visrequired in magnetizing a selected area. Saturation of a single crystalmaterial is achieved more easily than in polycrystalline materials and,thus, less current is required. For example, if the material is used toproduce the core of a miniaturized inductor by encapsulating apolycrystalline conductor, a higher and more uniformly repeatableinductance could be obtained from a single crystal device as comparedwith a polycrystalline device using the same amount of current.

It is also possible to embed or encircle a polycrystalline material within a single crystal structure and subsequently dissolve the encapsulatedpolycrystalline substance leaving holes, openings, or channels in thesingle crystal. Such structures might be useful in laser devices wheresingle "ice crystals are frequently used. The holes or channels might beused for circulating coolants through the crystal for removing heat.

Embed or encircle in addition to the ordinary meaning of such wordsincludes encapsulate and enclose wherein, for example, a polycrystallinesubstance is entirely surrounded by a single crystal. The terms alsoinclude situations wherein the polycrystalline material is not entirelysurrounded.

Another use of the process is for forming metal base transistors havingsingle crystal semiconductor layers on each side.

Other circuit schemes and devices may also be produced by the embeddingor encircling process.

Accordingly, it is an object of this invention to embed or encirclepolycrystalline materials in single crystal materials.

It is another object of this invention to :produce improved magneticdevices by use of a process for embedding or encircling polycrystallinematerials in single crystal materials.

It is still another object of this invention to provide processes forproducing a magnetic memory device.

A process has been invented for embedding or encircling polycrystallinematerial in single crystal material. It has been demonstrated that whena polycrystalline material and a single crystal substrate material areplaced in close proximity in a chemical vapor deposition chamber, and ifthe crystal structure of the single crystal substrate material issimilar to that of the depositing reaction product, the single crystalsubstrate will be the preferred deposition site. Furthermore, it hasbeen demonstrated that a critical rate of reaction may be establishedsuch that all of the deposition occurs on the preferred single crystalsubstrate material, thus allowing no polycrystalline deposition on thepolycrystalline material. Therefore, the critical rate of reaction maybe established empirically by observing deposition within anenvironment. The rate of reaction may be changed by varying the gas fiowrates of the reacting elements until a single crystal growth rate isestablished which predominates over the nucleation rate.

A critical rate of reaction may be determined for each material beingdeposited and for each substrate. Each combination of deposited materialand substrate material has a different critical reaction rate. That isto say that each combination of deposited material and substratematerial has a growth rate at which the deposition is single crystal innature rather than of a polycrystalline nature. Thus, no material isdeposited on a polycrystalline material which might be present in thereaction chamber since this would require nucleation. Although thepolycrystalline material is placed in the path of the crystal growth ofthe depositing material, the crystal structure of the deposit isinfluenced entirely by the single crystal substrate and thepolycrystalline material is embedded or encircled in the single crystaldeposit with no polycrystalline deposit inclusions.

In one embodiment of this invention, a polycrystalline material and asingle crystal substrate material are placed in close proximity in avapor deposition chamber. The crystal structure of the single crystalsubstrate material is similar to that of a deposition reaction productso that the single crystal substrate is the preferred depositionlocation. A critical rate of reaction is established and all of thedeposition occurs on the preferred single crystal substrate material andno polycrystalline deposition occurs on the polycrystalline material.

In another embodiment, a single crystal material is first deposited on asingle crystalline substrate and subsequently the polycrystallinematerial is deposited. Following deposition of the polycrystallinematerial at a designated location on the single crystal material, thesingle crystalline deposition is continued until the poly crystallinematerial is embedded or encircled, as desired.

In one specific application of the process, a magnetic memory device isprepared by producing a single crystal ferrite body which ismagnetically anisotropic and is susceptible to easy magnetization ingiven crystallographic direction. In one embodiment of the produceddevice, a plurality of electrical conductors in insulated crossoverrelationship are incorporated and substantially surrounded by theferrite body so that a magnetic orientation may be obtained in theferrite by passing electric current through one or more of suchconductors.

In another embodiment of the memory device produced by the inventiveprocess, after the electrical conductors are disposed on the singlecrystal ferrite surface 'having a preselected direction relative to thecrystal ferrite and approximately insulated at the crossover point,additional single crystal ferrite material is deposited thereover so asto encapsulate at least the crossover point in single crystal ferritematerial. For example, the direction of the conductors might beparallel, orthogonal or at an angle to a selected crystal direction.

It is a preferred feature of the process of the present invention thatthe ferrite body is formed by reacting selected metal halides and watervapor to epitaxially deposit the ferrite material in a preselectedcrystallographic form.

In the following description and examples, the process is described interms of producing a magnetic memory device by encapsulatingpolycrystalline conductors in a single crystal ferrite material. Itshould be understood that the description and examples are for thepurpose of illustrating embodiments of the broad inventive process forembedding or encircling polycrystalline materials in single crystalmaterials and that the description and examples are not exhaustive ofthe uses nor the scope of the invention. As indicated above, the processmay have many applications and may produce many differing devices.

Other objects and features of the invention will become apparent fromthe following description taken in light of the figures in which:

FIG. 1 is a representation of an apparatus used in embedding orencircling polycrystalline material in single crystal material.

FIG. 2 is a cross-sectional view of the apparatus of FIG. 1 taken online 2-2.

FIG. 3 is a cross-section of a portion of a magnetic memory device whichmay be produced by the present invention.

FIG. 4 is a pictoral representation of a memory system utilizing amagnetic memory device produced by the present invention.

FIG. 5 is a cross-section view of the memory device showing insulationbetween the conductors.

Referring now to FIG. 1, the apparatus of the present inventioncomprises a chamber 1, preferably of T shape and including inlet means 2for injecting gases into one end of the chamber 1, and an exhaust 18 atthe other end of member 4. The cross member 4 is surrounded by a heatingelement to control the temperature within the member 4. Supported insidechamber 1 are a plurality of spaced crucibles 5. The spaced cruciblesare each attached to a central holder rod 6 but may be maintained in acentral position by any well known means. Adjacent to the outer surfaceof chamber 1 and positioned to surround each crucible 5 is a heaterelement 7. Each element 7 may be controlled independently so that thezone in which each crucible 5 is located may be heated to a preselectedtemperature. Within the cross member 4 is a quartz holder 8 on whichsubstrates or crystals 10 are supported. The crystals 10 are locatedalong cross member 4 from a point where chamber 1 joins the cross member4 toward the exhaust port so that each is exposed 4 to a mixture of thegases flowing from inlets 2 and 3. Inlet 2 is connected to a source (notshown) of a dry mixture of He and Ar. Inlet 3 is connected to a source(not shown) in which helium, argon and oxygen are bubbled through waterto produce a mixture of inert gases, Water vapor, and oxygen, e.g., He,Ar, H 0, and 0 The substrates 10 on which the ferrite crystal isdeposited or grown are comprised of material having crystal structuresimilar to that to be deposited. For the purpose of describing theferrite memory produced by the invention, the substrate materialselected is MgO, although other substrate materials, e.g., MgAl O A1 0and other materials having the formula MeMe "O may also be utilized inproducing tre memory. The terms, Me and Me are defined hereinafter.

It ShOuld be pointed out that the process is not limited to use of aparticular substrate material or crystal orientation. It is not limitedto the use of spinel materials set forth herein. The process andmaterials used in the process are limited only by the crystalorientation of the deposited material and the process used in thedeposition. For example, the material may be deposited by chemical vaportechniques. If so, then various materials may be deposited. Thesubstrate material is then selected with a crystal orientation whichwill permit single crystal deposition thereon. The deposition rate isdependent on the type of substrate and deposited material.

The substrates 10 may be prepared by cleaving optical grade MgO along acleavage plane or by cutting the MgO into plates of desiredconfiguration along its other crystal faces. The plates are ground flatto produce a plate having a selected size and a selectedcrystallographic plane and then chemically polished in an acid etchsolution.

The substrates 10 are supported on holder 8 inside the cross member 4and a ferritic layer may be deposited as described in detailhereinafter.

The source materials 11 for producing the ferrite deposit on thesubstrate 10 are placed in containers 5 and heated to vaporization byvarious heater elements 7. The source materials placed inside containers5 may be Me'X Me"X or a mixture thereof where Me may be Li, Mg, Mn, Fe,Co, Ni, Cu, Zn, or Cd; where Me" may be Al, Cr, Mn, Fe, or Ti; and whereX is a halide (F, Cl, Br, I), provided that one of the Me or Me" is Fe,and the subscript a is either 1, 2, 3, or 4 to correspond with thevalence of the cation. Simultaneously with the heating of material 11,the above described carrier gases are admitted through inlets 2 and 3.

The following reaction takes place at the surface of the substrates 10to deposit a ferrite film on the MgO substrate crystals:

MO'XZ 2Me"X.. 31120 oz inert gases Me(Me Fe) 04 GHX inert gase The termferrite as used herein refers to compositions of iron oxide either aloneor in chemical combination with at least one other metallic oxide toform a magnetic material. Thus, the expression Me'(Me"lFe) O refersgenerally to these ferrite materials without reference necessarily toany particular stoichiometric or empirical composition. Most ferrites ofcommercial interest consist of one or two metallic oxides in chemicalcombination with iron oxide. Thus, the ferrites formed are preferablythose of commercial interest having low coercive forces, e.g., MnFe ONlFCgO MgFe204, ZnFe O (3111 6204, and combinations of these compounds.Other ferrite material may be used depending upon the desiredapplication.

After the first ferrite layers are deposited on the sub strates, thesubstrates are removed and placed in a con ventional vacuum depositionchamber (not shown). In the chamber, one or more polycrystallineconductors comprising a first array of parallel conductors are depositedon the substrate surfaces in a preselected direction relative to thecrystalline structure of the ferrite, by methods well known in the art,e.g., vacuum deposition or sputtering. Electrically conductive materialssuch as gold, silver, platinum,'or copper may be used, however gold ispreferred because of its excellent electrical characteristics. Theseconductors are preferentially oriented with respect to the crystal planeto provide modes of magnetization along different directions. (See Smithet al., Ferrites]ohn Wiley & Sons, 1959.)

After the first array of conductors is deposited, patterns of insulationmaterial are deposited in a selected pattern to coat portions of theconductors of the first array. Such insulation materials as MgO, A1 andBaF may be deposited by standard deposition techniques. Subsequently,one or more conductors constituting a second array of conductors arevacuum deposited in a manner so as to crossover at a preselected angleto the first array and yet be insulated therefrom by the insulationmaterials previously deposited.

After the conductor arrays have been deposited with appropriateinsulation at each crossover point, the substrate is preferably placedin the chamber and a second ferrite body is deposited on this existingferrite layer and around the conductors to encircle at least thecrossover points of the conductor arrays within the single crystalferrite mass. The entire conductor may, of course, be encircled.

Also, instead of embedding or encircling a plurality of conductorpatterns or arrays, it may be preferable in some instances to encircle asingle conductor array and then deposit a second array and encircle it.In that embodiment, single crystal ferrite would separate the conductorarrays whereas in the previous embodiment, the conductor arrays wereseparated by an insulation material other than the ferrite.

FIG. 2 is a cross-sectional view of the chamber illustrating withgreater clarity the position of the cross member 4 and crystals 10inside the chamber.

In FIG. 3, a cross-section of an encapsulated conductor fabricated inaccordance with the above described preferred processes is illustrated.As shown therein, layer 12a represents the first ferrite depositionlayer on substrate 13, conductor array 14 represents one of theconductors of an array, while the second conductor array runs orthogonalto conductor array 14 and cannot be seen in this cross-section. Theferrite material 12b provides the completion of encirclement. Apictorial representation of the device shown in FIG. 3 is shown in FIG.4, which shows the plurality of conductor arrays 14 and 16 angularlydisposed with each other whose encirclement is completed by the ferrite12b. Ferrite has been deposited on a substrate 13 and the conductors areinsulated from each other by insulation 17.

FIG. is a cross-section view of a portion of FIG. 4 showing insulation17 between conductor arrays 14 and 16.

The practice of the inventive method for producing, in one embodiment,an epitaxial ferrite memory device is described more fully withreference to the following examples:

EXAMPLE I The substrate material, MgO, is prepared by cleaving thecrystal along a (100) cleavage plane into approximately one-inch squaresubstrates. After cleaving, the substrate is mechanically ground fiat ona series of metallographic papers to the 4/0 size. They are thenchemically polished in a 3:1, concentrated H PO concentrated H 80etching solution heated to 125 C. for two hours. After the two-hours ofetching, the substrates are given a thorough hot water rinse.

A quartz T shaped apparatus of FIG. 1 having a 45 mm. I.D., was utilizedas the deposition chamber. A quartz holder is used to support aplurality of MgO crystals in the middle of the cross member 4 of theapparatus. Quartz crucibles 5 supported by quartz rods 6 contained thesource materials 11. These crucibles are each carefully located in thechamber 1 with each source material having an individually controlledelectrical heater 7. In this example, the source materials are MnBr FeBrand NiBr arranged in the chamber 1 in the stated order from top tobottom. This order is determined by the temperatures necessary tovolatilize the various source materials. After the crystals and thecontainers are placed in the cross member 4, the gas flows are adjustedand the cross member 4- and suspended substrates 10 are heated to thedesired temperature of about 1000 C. The various heating elements 7 forthe source materials 11 in the chamber 1 are then turned on. The MnBr isheated to about 800 C., the FeBr to about 700 C. and the NiBr to about600 C.

To obtain maximum interaction between the source material vapors,mixtures of helium and argon are used to carry the source materialvapors and the water vapor into contact with the substrate surfaces. Amixture of 5 cubic feet per hour of He and 10 cubic feet per hour of Aris used to carry the source material vapors. A mixture of 6 cubic feetper hour of He and 3 cubic feet per hour of Ar is used to carry thewater vapor. When the desired temperatures are reached, the carriergases are rechanneled through a water bubbler, thus causing Water Vaporto be carried into the reaction chamber. The fiow rates for the fluidswas established empirically to promote single crystal growth rather thannucleation. Ferrous iron (Fe+ is oxidized to ferric iron (Fe+ by theaddition of 0.08 cubic feet per hour of O to the reaction chamber at thetime the desired temperature is reached.

The reaction to form the ferritic layer was as follows:

1000 C. 0.3MnBr 0.55 NiBlz 2.15 FeBrz 3H2O %O2 In? As a result of thisreaction, an epitaxial, single crystal ferrite layer or body isdeposited on the MgO substrate.

X-ray examination may be utilized to confirm that the ferrite layer is asingle crystal.

The crystal is then placed in a conventional vacuum chamber fordeposition of the first gold conductor array through a mask positionedon ferrite layer. This array may be deposited parallel with the l10 orcrystal directions.

The gold conductors were 2 mils wide and 0.25 mil thick and were spacedon 10 mil centers on the substrate layer. The conductor size may bevaried. The conductor mask is then removed and replaced by a transversemask for depositing insulation material on the conductors. Theinsulation, BaF may be limited by a mask or equivalent mechanism to theconductors at the point of crossover. On the other hand, it may alsocover the entire array of conductors and etched to produce the desiredarrangement of insulation pads. The insulation material may be depositedby any method well known in the art.

After the insulation deposition was completed, a second mask is insertedinto the chamber to define a second array of conductors disposedcrosswise at a preselected angle to the [first deposited conductorarray. The preselected angle of the second array in this example wasnormal to the first, although other angular relationships may beutilized. In this manner, the second array of deposited conductorsoverlaps the first conductor array in crossover relation and isinsulated therefrom by the insulation material previously deposited.

After the second conductor array is deposited, the substrate with theconductors thereon is placed in the reaction deposition chamber of FIG.1 and a second layer of single crystal ferrite is deposited as describedabove. The second layer of ferrite single crystal, together with thefirst ferrite layer on which it was deposited, encircles the conductorarrays within the single crystal epitaxial ferrite, thereby providing anepitaxial ferrite memory device. In this embodiment, the second layer offerrite crystal is a continuation of the single crystalline structure ofthe first layer.

EXAMPLE II Using the apparatus and process steps of Example I, thesubstrate material is cut so as to provide a (110) crystallographicplane as the substrate surface. The conductor arrays are then depositedon a ferrite layer, as described above, parallel to the 001 direction inthe (110) plane or at 45 to that direction. The single crystal ferritelayer was then deposited as described in Example I, thereby providing anepitaxial ferrite memory device.

EXAMPLE 111 Using the apparatus and process of Example I, the substratematerial is cut so as to provide a (111) crystallographic plane as thesubstrate surface. The conductor arrays are then deposited, as describedabove, parallel to the 111 direction in the (111) plane or parallel tothe 112 direction, thereby providing an epitaxial memory device.

EXAMPDE IV Using the apparatus source materials and process stepsdescribed in Example 'I, the temperature of the source material heaterswas varied to produce controlled variations in the ferrite compositions.The source temperature range was from about 500 C. to about 900 C. withthe ferrite composition varying from high nickel and low manganeseferrites to low nickel and high manganese ferrites. Thus, by appropriateselection of the temperature the deposition may be controlled to providea desired ferrite composition. All temperature conditions within therange produced single crystal ferrite memory devices of acceptablequality.

EXAMPLE V Using the apparatus and process steps described in Example I,the bromides of Mg and Co were substituted for the bromides of Mn and Niutilized in Example I. The modified process produced single crystalferrite memory devices of acceptable quality on a MgAl O substrate.

Other variations may be made without departing from the spirit and scopeof the invention. For example, other polycrystalline materials as Wellas electrical conductor arrays may be utilized. Conductors or otherpolycrystalline materials may be embedded or encircled for formingminiaturized inductors. Metal base transistors as well as other circuitcomponents including integrated circuits may be at least partiallyformed by use of the process. For example, polycrystalline noble metals,copper, and other conductor metals, oxides, and soluble inorganics, maybe similarly embedded or encircled in Si, Ge, GaAs, CdTe, CdS, A1 andMgO grown in single crystal form around such polycrystalline material.The invention may be used to produce other devices consistent withencapsulating a polycrystalline material in a single crystal material.

These and other modifications in the processes of the present inventionwill be apparent to those skilled in the art. Therefore, the presentinvention is not limited to the specific details of the examplesdescribed but only by the appended claims.

We claim:

1. A process for embedding polycrystalline electrical 8 conductors insingle crystal ferrite, said process comprising the steps of:

(a) heating in a chamber a single crystal substrate selected from theclass consisting of MgO, MgAl O and A1 0 to a temperature on the orderof 1,000

(b) vaporizing, at other locations in said chamber, halides of iron andone more source materials selected from the class consisting of Mn, Ni,Fe, Mg and Co,

(c) transporting the vaporized halides to said heated substrate in acarrier gas comprising approximately 5 cubic feet per hour of helium andapproximately 10 cubic feet per hour of argon,

(d) transporting water vapor to said substrate in a carrier gascomprising a mixture of approximately 6 cubic feet per hour of heliumand 3 cubic feet per hour of argon, whereby said halides and said watervapor react to form an initial layer of single crystal ferriteepitaxially atop said substrate,

(e) depositing an array of gold conductors atop said initial ferritelayer,

(f) reheating the combined substrate, initial layer and conductors insaid chamber to a temperature on the order of l,000 C., and

(g) repeating steps c and (1, thereby preferentially depositingadditional single crystal ferrite atop said initial layer, said ferriteembedding said conductors.

2. The process defined in claim 1 wherein said substrate comprises MgO,wherein said halides comprise MnBr heated to about 800 C. to achievevaporization thereof, FeBr heated to about 700 C., and Ni-Br heated toabout 600 C., and wherein approximately 0.08 cubic feet per hour of 0also is introduced into said chamber, whereby the deposited ferrite hasthe formula 3. The process as defined in claim 1 wherein between steps eand f are added the steps of:

depositing an insulating material comprising BaF atop at least a portionof said conductors, and

depositing a second array of conductors crossing said first array andinsulated therefrom by said BaF 4. The process defined in claim 1wherein said source temperature range is varied from about 500 C. toabout 900 C. to control the composition of nickel and manganese in thedeposited ferrite.

5. The process defined in claim 1 wherein said source materials compriseMgBr CoBr and FeBr and wherein said substrate comprises MgAl OReferences Cited UNITED STATES PATENTS 3,189,973 6/1965 Edwards et al.l48174X ALFRED L. LEAVITT, Primary Examiner J. H. NEWSOME, AssistantExaminer U.S. Cl. X.R.

Patent No. 3 574 579 ated April 13 1971 Inventor(s) Pulliam et 1.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Claim 1 column 8 line 8 after "one" and before "more" insert or Signedand sealed this 4th day of January 1972 (SEAL) gAttest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer ActingCommissioner of Pate

